Change-speed gearing



E. REEVE.

CHANGE SPEED BEARING.

APPLICATION FILED APR. 24, 1919.

Patented Jan. 11, 1921.

W fawn UNITED STA ES I nnwann annvn, or Bmumenm, ENGLAND, assrenon r0 m mmco-nmra PATENT OFFICE.

SYNDICATE LIMITED, 01 LONDON, ENGLAND.

CHANGE-SPEED GELRING.

- Specification. Letters Patent. Patented J an. 11, 1921.

Original application filed September 2 5, 1918', Serial No. 255,554. Divided and this application filed April 24, 1919. Serial 110. 292,455.

Speed Gearing, of which the following is a specification. v r

This invention relates to change speed gearing of the spur epicyclic type in which the change of'speed ratios'is effected by the aid of electromagnetic clutches, the gear beindicated diagrammatically only and thatthe details of their construction andof the vmountmg of their i armatures are not of the which the present application'is a division,

is characterized by a construction such that three co-axial sun-wheels employed therein, two driving and one driven, are not only coaxial but are of three different sizes; that the driven sun-wheel is larger than the other two; and that the three planet-wheels which gear with them (a) are rigidly connected to one another and turn about a planetary axis parallel to the axis of the suns, and (b) have the smallest of the three planets geared to the largest of the three suns whereby a reverse is obtainable as well as three forward speeds in the manner hereinafter explained; and that two of the forward speeds are obtained by holding stationary the support of the planetary shaft.

An alternative construction of electroject-matter, of the present invention. It differs from that which 'is above referred to by the addition of an extra planet pinion fixed to the others, and of a brake-controlled fourth sun-wheel with which it gears, the said fourth sun-wheel being loose and turning on bearings that are co-axial with the driving shaft and being also combined with a stationary electro-magnetic brake appro priated to it, whereby it can be locked to and released from the stationary casing 'of the mechanism to enable additional speeds to be obtained, forward or reverse as desired. The related planetar pinions may be divided and laced on di erent parallel shafts as will hereinafter appear, provided that they are so geared together that they all turn at the angular velocltles that they would possess were they all en bloc on one planetary shaft. -The accompanying drawing is a view in vertical central longitudinal section of a construction of gear according to the present inventionand referred to above as having an extra planet pinion and a brake-controlled fourth sun-wheel with which it gears. It is to be understood that in the drawing the electro-magnetic clutches and brakes are present invention'and may be of any convement type.

' With reference to the drawing a driving shaft A which may conveniently be operated by a petrol motor, turns in ball-beann s a in the fixed stationary casing X of t e mechanism. Two driving sun-wheels D E of different diameters, are free to turn independently of the driving shaft A with which they are co-axial. The smaller wheel E of'thesetwo is fixed on a spindle e which is supported at the left-hand end by ballbearings e supported in a cavity in a disk A secured to the right-hand end of the driving shaft A The right-hand end of the spindle e is supported in the hollow left-hand end of the driven spindle A and the said in the casing X. The larger, D of the two sun-wheels D E is provided with a sleeve D which encircles and can turn in relation to the spindle e by which it is'supported. The driven spindle A can be connected in any suitable manner to, say, the road-wheels 1 of an automobile vehicle, or to any other device which the change-speed gear is to actuate. The circular electro-magnets D and E of two electro-magnetic clutches are fixed to and turn with the disk A formed on the driving shaft A the armatures D and E of these clutches D and E turn respectively with the disk E fixed to the sleeve Current conveyed by any suitable means to the electro-magnets D and E, or either of "them, enables the suns D and E or either of them, to be clutched to the disk A so as to turn with itand the driving shaft A A stationary circular electro-magnet G is spindle fixed to the casing X and with an armature G carried on the disk D aforesaid, forms an electro-magnetic brake. This when energized, holds the disk D stationary and with it the larger D of the two driving sunwheels D E A third sun-wheel A, hereinafter termed the driven sun-wheel, is fixed to the driven shaft A. It is co-axial with but larger than the other two sun-wheels D E in order that it may cooperate with the smallest of three out of four planetary wheels hereinafter referred to for the purpose inter alia of effecting a reverse drive of the driven shaft A in the manner hereinafter described.

A stationary annular electro-magnet K is fixed to the stationary casing X; its armature S is fixed to the rotatable support S, hereinafter described. By energizing the electro-magnet K the support S can be locked to the stationary casing X when required. When it is thus locked, two of the forward speeds of the gear are obtained, as will be hereinafter explained.

The left-hand end of the support S is carried on ball-bearings 8 supported on the outside of the sleeve 1), but the right-hand end of the support is carried on ball-bearings s which are borne on the outside of the sleeve of the fourth sun-wheel aforesaid, presently to be again referred to. This is a fourth sun-wheel L fixed to a sleeve Z with \which it can turn in relation to the driven shaft A with which latter and with the driving shaft it is co-axial. To this sleeve Z is fixed the disk Z carrying an armature Z for a stationary annular electro-magnet L fixed inside the casing X of the gear. By means of this electro-magnet L and the armature Z a stationary electro-magnetic brake is constituted whereby the fourth sunwheel L can be locked to and released from the stationary casing.

Planetary spindles B and B parallel to the driving and driven shafts A and A? are fixed in bearings 12 in the aforesaid support S which as will be seen from the drawing turns about an axis that is co-axial with the driving shaft.

On the first planetary spindle B in the support S are two planetary pinions 2, 3 co-axial with it and which rotate on it and are connected to one another. On the second planetary spindle B are three planetar pinions 1, 2 and 4 co-axial with it and whic rotate on it and are connected to one another. The planetary pinion 2 on the spindle B is gearedto the smallest sun-wheel E and the planetary pinion 3 on the spindle B is geared to the driven sun-wheel A The planetar pinion 1 on the second planetary 2 is geared to thelar er of the driving sun-wheels D the secon planetary pinion 2 on the shaft B? being geared to the smallest sun-wheel E and the third planetary pinion 4 on the planetary spindle B being geared to the brake-controlled fourth sun-wheel L aforesaid.

There might be as shown in chain-lines a planetary pinion 1 on the shaft B of the same size as that on the shaft B and there might be on the shaft B a planetary pinion 3 of the same size as the pinion 3 on the shaft B Also, a pinion 4; might be placed on the shaft B as well as on the shaft B By such modifications the two planetary shafts B B and the groups of pinions upon them would be identical.

The operation of the device illustrated in the drawing will now be described. To obtain the first forward speed the fourth sunwheel is held stationary by the electro-magnet L The clutch E is energized whereby the smaller driving sun-wheel E is rotated. This rotates the planetary pinions 2 with which it gears and turns them and the pinion 4 about their own axes; but the pinion 4 being in gear with the stationary fourth sunwheel L, imparts to the support S by rolling along L, a motion of translation in a sense opposite to that in which the driving shaft turns. But as the pinion 3 which partakes of the rotary andtranslational motion of the wheels 2, 3 and 4 is larger than the pinion 4, the said pinion 3 imparts to the driven sun-wheel A a slow motion of rotation in the same sense as that of the driving shaft.

. To obtain the second forward speed, the support S is held stationary by the brake K; the clutch E is energized and the sun-wheel E is driven. The latter turns the planetary pinion 2, which, the support S being stationary, imparts rotation about their common stationary axis to the pinion 3 and this in turn drives the driven sun-Wheel A in the same sense of rotation as that of the driving shaft.

To obtain the third forward speed the brake K remains energized but the clutch I) is energized instead of the clutch E. This leads to rotation of the sun-wheel D which driving the pinion 1, causes the pinions 2 (and incidentally the wheel E and 3 to turn, the latter rotating the drivenv sunwheel A andshaft A A fourth forward speedv (a' direct or through drive) is obtainable by clutching both the sun-wheels D and E to the driving shaft by means of the clutches D and E; this by reason of the difference in diameters of the sun-wheels D and E carries the planetary pinions and the suport S. around bodily so that the pinion 3 in this bodily motion of translation, turns thedriven sun-wheel A in the same sense and with the same angular velocity as that of the driving-shaft A ing inthe order illustrated in the drawing,

would be intermediate between the first and second forward-speeds above referred to.

To obtain a reverse in the gear illustrated ing the electro-magnet G and the wheel E is rotated by energizing the clutch electromagnet E. It results under these circumstances that the planetary spindle B is given by the rolling of planetary pinion 1 over the. sun-wheel D- as over a circular track, a motion of translation around'the driving-shaft A in a sense opposite to that in which the driving-shaft is turning, and

the planetary pinion 3 partakes of that moton of translation. If the planetary pinion 3 were of. the same size as the planetary pinion 1 it would leave the drivenv sunwheel A stationary, but as it is smaller than the planetary pinion 1 it takes the sunwheel A with it in a'direction the reverse of that in in".

. Tn the construction illustrated the pinion 4 running around .upon the sun-wheel L when the latter is stationary, gives the sun wheel A two velocities, according as the driving force is supplied from the sunwheel D or from the sun-wheel E The sense of these two velocities imparted to A which the driving-shaft is turnis that of the sense 'of rotation of the drivare shown in the vertical plane of the drawmg it is to be understood that there may be several of these shafts and the pinions on the said shafts being set parallel with one another at suitable equal angular intervals apart around the main axis of the mechanism, as is common in epicyclic gears.

In the construction shown" in the drawing the gear-wheels areall inclosed in the support S which is a hollow casing; this can easily be made oil-tight so that the gear may be run in a lubricant of'a kind different from that employed for the clutches, so

that the best lubricant can be selected for the different conditions of working in the gear and in the clutches. the wheel D isheld stationary by energiz- What I claim as my invention and desire to secure by Letters Patent is In an electro-magnetic change-speed and reverse gear of the spur-wheel epicyclic type, the combination of a driving-shaft, a stationary support therefor, two driving sun-Wheels of different diameters loose and turning on bearings that are coaxial with the driving shaft, two rotatable electromagnetic clutches whereby they may be clutched to and released from the driving shaft selectively and collectively, and a stationary electro-magnetic brake whereby the larger of the two driving sun-wheels can be locked to and released from the said sta tionary support of the driving-shaft, a driven sun-wheel, A coaxial with but larger than the two driving sun-wheels, a brake-controlled sun-wheel L loose and turning on bearings that are coaxial with support for the said planetary spindle,

' planetary pinions on and coaxial with the said, planetary spindle which pinions are fixed to one another and are in gear with the corresponding sun-wheels, and another stationary electro-magnetic brake whereby the rotatablesupport can be locked to the aforesaid stationary support for the obtainment of two of the forward speeds as hereinbefore described.

In testimony whereof I afiix my signature.

EDWARD REEVE. 

